National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA.
Nat Commun. 2013;4:2671. doi: 10.1038/ncomms3671.
Contacting ferromagnetic films with normal metals changes how magnetic textures respond to electric currents, enabling surprisingly fast domain wall motions and spin texture-dependent propagation direction. These effects are attributed to domain wall chirality induced by the Dzyaloshinskii-Moriya interaction at interfaces, which suggests rich possibilities to influence domain wall dynamics if the Dzyaloshinskii-Moriya interaction can be adjusted. Chiral magnetism was seen in several film structures on appropriately chosen substrates where interfacial spin-orbit-coupling effects are strong. Here we use real-space imaging to visualize chiral domain walls in cobalt/nickel multilayers in contact with platinum and iridium. We show that the Dzyaloshinskii-Moriya interaction can be adjusted to stabilize either left-handed or right-handed Néel walls, or non-chiral Bloch walls by adjusting an interfacial spacer layer between the multilayers and the substrate. Our findings introduce domain wall chirality as a new degree of freedom, which may open up new opportunities for spintronics device designs.
与正常金属接触的铁磁薄膜会改变磁织构对电流的响应方式，从而实现令人惊讶的快速畴壁运动和自旋织构相关的传播方向。这些效应归因于界面处的 Dzyaloshinskii-Moriya 相互作用引起的畴壁手性，这表明如果可以调整 Dzyaloshinskii-Moriya 相互作用，那么就有可能对畴壁动力学产生影响。在选择合适衬底的几种薄膜结构中观察到了手性磁性，其中界面自旋轨道耦合效应较强。在这里，我们使用实空间成像技术可视化了与铂和铱接触的钴/镍多层膜中的手性畴壁。我们表明，通过调整多层膜和衬底之间的界面间隔层，可以调整 Dzyaloshinskii-Moriya 相互作用，以稳定左手或右手 Neel 壁或非手性 Bloch 壁。我们的发现引入了畴壁手性作为一个新的自由度，这可能为自旋电子学器件设计开辟新的机会。
